In order to meet the increasing demand for wireless data traffic since the commercialization of 4G communication systems, the development focus is on the 5th generation (5G) or pre-5G communication system. For this reason, the 5G or pre-5G communication system is called a beyond 4G network communication system or post long-term evolution (LTE) system.
Consideration is being given to implementing the 5G communication system in millimeter wave (mmWave) frequency bands (e.g., 60 GHz bands) to accomplish higher data rates. In order to increase the propagation distance by mitigating propagation loss in the 5G communication system, discussions are underway about various techniques such as beamforming, massive multiple-input multiple-output (MIMO), full dimensional MIMO (FD-MIMO), array antenna, analog beamforming, and large-scale antenna.
Also, in order to enhance network performance of the 5G communication system, developments are underway of various techniques such as evolved small cell, advanced small cell, cloud radio access network (cloud RAN), ultra-dense network, device to device (D2D) communication, wireless backhaul, moving network, cooperative communication, coordinated multi-points (CoMP), and interference cancellation.
Furthermore, the 5G communication system adopts an advanced coding modulation (ACM) scheme such as FQAM (i.e., combination of frequency shift keying (FSK) and quadrature amplitude modulation (QAM)) and sliding window superposition coding (SWSC) and an enhanced network access scheme such as filter bank multi carrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA).
Meanwhile, there is a need of prioritizing public safety communication in comparison with normal communications in a public safety network (public safety LTE or PS-LTE).